From first principles: Some sized and equipped military force is required for a credible NATO defense from Russia. The origins of that force's components is a

From first principles: Some sized and equipped military force is required for a credible NATO defense from Russia. The origins of that force's components is a zero sum game. If they don't come from one country, they must come from another. The US currently spends ~3.5% of GDP on its military. The EU (in total) spends ~1.6%. I believe the UK is at ~2.5%. The NATO target is 2% of GDP. See specifically, graphs 2-4: https://www.nato.int/nato_static_fl2014/assets/pdf/2021/6/pdf/210611-pr-2021-094-en.pdf https://www.nato.int/nato_static_fl2014/assets/pdf/2021/6/pd... If the US spent less, it's possible Europeans would not choose to make up the difference. But if they didn't, they'd certainly be less secure. It's a complicated topic, but the idea that the US is paying for more European defense than Europeans is well-supported.